Advice?

Rear hatch open warnig constantly,even though its closed.could it be comfort control unit?

ive had this before and was the boot catch , its the one attached to the tailgate , i took it off and gave it a clean out as was full of gunk that had stuck to the mechanism and micro switch from years of lubing the catch up id imagine but simple to fix if yours has the same issue as mine

Other sign it's the catch as JIGSAW suggested is the boot light not switching on (or off)

Cheers Spike